1. Field of the Invention
The present invention relates to a substrate processing apparatus that applies film deposition, an etching process, or the like on, for example, a semiconductor wafer by plasma processing.
2. Description of the Related Art
In a substrate processing apparatus such as a CVD (Chemical Vapor Deposition) apparatus, which applies film deposition on a substrate such as a semiconductor wafer (hereinafter, simply referred to as a wafer) and a glass substrate for a LCD (Liquid Crystal Display), and an etching apparatus that applies an etching process on such a substrate, the inside of a process chamber is exhausted via an exhaust port disposed, for example, in a lower portion thereof while plasma process gas is being introduced from above the substrate.
In such a substrate processing apparatus, SiO2, SiN, SiOCH, CF polymer, and the like (reaction products) stay to be deposited in the process chamber after the plasma processing. Such deposits are problematic since they float in the process chamber thereafter to adhere to the substrate. Therefore, the inside of the process chamber is exhausted after the plasma processing, using the aforesaid exhaust port. Such a substrate processing apparatus is disclosed in, for example, Japanese Patent Laid-open No. Hei 9-168732 (see FIG. 1, [0008], and so on).
The above-described substrate processing apparatus, however, has a problem that the gas flow on the substrate surface is disturbed because the exhaust port is provided in the lower portion of the process chamber, so that process uniformity is not maintained.
Here, a possible measure for solving the problem may be, for example, disposing the exhaust port as close as possible to the substrate surface, but this structure has a problem that the reaction products stay to be deposited in the lower portion of the process chamber (for example, on a side face and a bottom side of a process stage, a lower portion of a stay of the process stage, and so on).